1. Field of the invention
This invention relates to a micro structure that causes an elastic deformation at least at a part thereof a cantilever composed of the micro structure, a scanning probe microscope providing the cantilever and a method for measuring deformation quantity for the micro structure.
2. Description of the Related Art
As micro structures that cause an elastic deformation at least at a part thereof, for example, there are cantilevers which constitute MFM: Magnetic Force Microscope and AFM: Atomic Force Microscope, which are kinds of SPM: Scan Probe Microscope, in addition, there is the cantilever which constitutes SNOM: Scanning Near-field Optical Microscope.
For example, the cantilever constituting AFM holds a probe in its front end, and the probe is placed closely toward the surface of a specimen, which are fixed on experimental beds or vibrating in high frequency. The laser beam is irradiated on an upper surface nearby the probe that is set lower surface of the front end of the cantilever through optics and thereby, the deflection quantity of the cantilever is measured using intensity ratio of reflection beams from the cantilever detected by a photodetector which is divided to four parts: upper, lower, left and right. The three-dimensional-shapes of unevenness or the like on the surface of the specimen is observed by calculating atomic force working with the probe and the surface of the material from this deflection quantity (for example, see patent document 1). The technology described above is referred to the first prior art as follows.
Additionally, there is the other type of the conventional AFM in which the cantilever is composed of a piezo resistance element and the deflection quantity of the cantilever is measured as a change of the value of the piezo resistance. This type of AFM is provided with a signal detection system that applies constant-voltage-bias to the cantilever and converts detected input current signal to change of resistance to an output voltage signal; an offset signal detection system that detects the component of an offset signal included in the output voltage signal from the signal detection system and removes it (for example, see patent document 2). Hereafter, the technology described above is referred to the second prior art.
[Patent Document 1]                Japanese Patent Publication Number H6-323843 (paragraphs [0008] and [0009], and FIGS. 1 and 2)        
[Patent Document 2]                Japanese Patent Publication Number 2000-304756 (claim 1, paragraphs [0010] to [0014], and FIGS. 1 and 3)        